1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method for processing substrates, such as semiconductor wafers or glass substrates for LCDs (liquid crystal displays), in an atmosphere containing a vapor and a gas.
2. Description of the Related Art
Generally, a semiconductor device fabricating method includes a step of forming a predetermined circuit pattern on-a semiconductor wafer by photolithography. More specifically, a semiconductor device fabricating method includes series of steps of applying a liquid photoresist to a semiconductor wafer cleaned by a cleaning process to form a photoresist film, exposing the photoresist film to a desired light pattern, subjecting the exposed photoresist film to a developing process to form a photoresist mask, subjecting the semiconductor wafer to an etching process and a doping process, and removing the photoresist mask, i.e., the photoresist film, from the semiconductor wafer.
A known resist film removing method of removing a resist film from a semiconductor wafer immerses the semiconductor wafer in a cleaning tank holding a chemical liquid called SPM solution containing sulfuric acid and hydrogen peroxide, or a chemical liquid containing ozone. The known resist film removing method has problems that particles contained in the chemical liquid adhere to the semiconductor wafer when the semiconductor wafer is immersed in the chemical liquid, and particles removed from the semiconductor wafer and suspended in the chemical liquid adhere to other semiconductor wafers. The disposal of waste liquid produced by the resist film removing method using the SPM solution is costly.
A recently proposed resist film removing method includes a step of altering a resist film formed on a semiconductor wafer with a gas containing steam and an ozone-containing gas, and then subjecting the semiconductor wafer having the altered resist film to a water cleaning process to remove the resist film. The altering step is carried out by supplying steam and the ozone-containing gas into the hermetically-closed processing vessel accommodating a semiconductor wafer.
However, a mixed gaseous fluid produced by thus mixing steam and the ozone-containing gas is highly corrosive, corrodes various component members of the processing apparatus, such as a wafer holder, placed in the processing vessel, and corroded parts produce particles that contaminate the semiconductor wafer.